I liked del.icio.us, it was online bookmark sharing, but with actual people I knew, and it had genuinely useful category tagging. I guess it was basically replaced with https://old.reddit.com and maybe twitter.
Isn’t Pinboard (Who bought delicious) very similar? I also see bookmarks of my friend there, recently switched to Raindrop though as it’s much more maintained.
There's also Readeck, which is a similar self-hosted tool that also captures some text content it can discover (i.e. article text and images, video transcripts, highlighted sections) and can export collections to RSS feeds and epub.